Urinary catheter assemblies for draining the bladder are increasingly used for intermittent as well as indwelling or permanent catheterisation. An intermittent urinary catheter is in most cases a single-use product used to immediately drain the bladder by inserting the catheter into the urethra. After drainage of the bladder, the catheter is withdrawn from the urethra again. This procedure normally takes less than ½ hour, typically 10 minutes. An important feature for the intermittent catheter is to ease the insertion into the urethra. This is done by providing the intermittent catheter with a low frictious surface. Non-limiting examples of such are hydrophilic coated catheters which are subsequently wetted by a swelling medium in order to produce a low friction surface, or oil or water based gel which is applied to the catheter before insertion into the urethra.
Indwelling catheters, as the name also implies, dwells in the body for at least some time. Contrary to intermittent catheters, an indwelling catheter is inserted by a trained professional, typically a physician or a nurse and is left inside the patient for days or weeks. As the indwelling catheter is left inside the patient for a considerable amount of time, such catheters will typically be larger in size and have a different surface compared to intermittent catheters. As an example, hydrophilic coated catheters, where the coating absorbs a considerable amount of liquid for a low frictious surface (swelling degree >100%), will not be suitable for indwelling catheters, because the hydrophilic surface coating would stick inside the mucosa of the urethra if left inside the body for a longer period, due to the hydrophilic coating transforming from being highly lubricious when fully wetted to being adhesive when the hydration level of the coating is reduced.
Typically, urinary catheters are used by patients suffering from urinary incontinence or by disabled individuals like paraplegics or tetraplegics, who may have no control permitting voluntary urination and for whom catheterisation may be the way of urinating.
Normally, the urine is submitted from the urinary catheter directly into the toilet. However, urinary catheters exist in combination with bags for collecting the urine. Typically, such combined devices are of a considerable length and may therefore be troublesome to handle and to bring along, not least for the individuals for whom catheterisation is a daily-life procedure, wherein catheterisation takes place several times a day and wherein the used urinary draining devices must be disposed via the garbage collection.